A variety of derivatives of Zn2+-cyclen complexes have been designed as prototypes of selective receptors of 'imide'- containing nucleobases, thymine (dT) and uracil (U), in aqueous solution at physiological pH. The Zn2+-cyclen complexes with polyaromatic pendants possess recognition efficiency in terms of Kd on the order of 10 μM in single- and double-stranded DNA (or RNA) to disrupt A-dT hydrogen bonds in double-stranded nucleic acids. A direct correlation was found between the binding of Tat to TAR RNA and up-regulation of HIV-1 mRNA transcription. The potent inhibition of HIV-1 TAR RNA-Tat peptide binding by Zn2+ complexes was described.